Control of Pierce's Disease through Areawide Management of Glassy-Winged Sharpshooter (Hemiptera: Cicadellidae) and Roguing of Infected Grapevines

Abstract

The General Beale Pilot Project serves as a case study for the use of areawide monitoring and treatment programs for glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar), and monitoring and roguing programs for grapevines infected with Xylella fastidiosa, to achieve regional management of Pierce's disease. The Project is located in southeast Kern County, CA, and contains ∼2,800 ha of citrus and grapevines grown within approximately 50 km2. For nearly 20 yr, an average of 470 traps have been used to monitor GWSS populations regionally by the California Department of Food and Agriculture, and to inform coordinated, areawide treatments by the USDA-APHIS Areawide Treatment Program to overwintering GWSS in citrus. Grape growers were responsible for treating their own vineyards, and for the roguing of infected grapevines based on surveys provided by the University of California. Herein, we provide a history of the General Beale Pilot Project, broken down into six eras based on levels of Project success, which incorporate data on GWSS captures, pesticide use, and disease incidence. We describe patterns of success related to the regional coordination of effective treatment and roguing programs that can be used by grape and neighboring citrus growers for areawide management of Pierce's disease. We conclude by describing current and future challenges for Pierce's disease management, including pesticide availability and resistance, GWSS refuges, the inability to detect and rogue infected vines in the year they become infected, and the sustainability of voluntary programs that rely on public funding.